1. Field of the Invention
The present invention relates to a multi-cylinder internal combustion engine which includes at least two cylinders each accommodating therein a piston, and valve actuating cam shafts disposed to extend over respective cylinder heads.
2. Description of the Prior Art
Heretofore, a multi-cylinder internal combustion engine has been formed to include a single common crankshaft which is interlocked through a timing device with cam shafts disposed to extend over respective cylinder heads.
In the mentioned multi-cylinder internal combustion engine, when two cylinders are arranged in a horizontally opposed form or V form in order to reduce vibrations, the cylinders must extend away from each other with the crankshaft therebetween. Such an arrangement impairs compactness of the engine. Further, a relatively long distance must exist between the crankshaft and the cam shaft, increasing the size of the timing mechanism connecting both the shafts. This requirement also impairs compactness of the engine.
Moreover, when coupling a transmission to a horizontally opposed type or V type engine, the transmission is arranged adjacent one end or one side of the crankshaft so that it is spaced from the cylinders.
Such an arrangement results in the engine and transmission assembly being large. With such engines, it is difficult to design an arrangement for small-sized vehicles such as motorcycles.